Strengthening of R.C beams with openings created after casting using F.R.P

الملخص EN

Web openings in beams have found many applications in practice such as they provide convenient passages of electrical and mechanical conduits.

Over the past several decades, many researchers exerted great efforts to predict and interpret the behavior of beams with web openings.

They recommended convenient methods for the design of such beams.

These methods are successfully used if openings were decided before casting of beams.

But, what will be the case if it is required to provide new openings in existing beams? The current work aims to give a satisfactory answer for this question, in which CFRP were used to strengthen and improve the behavior of beams with created openings.

Eighteen reinforced concrete beams with rectangular cross section (13 x 25 cm) were tested under two concentrated static load.

Three of the beams were taken solid without openings as control beams.

Each one of the other beams was provided with a rectangular web opening of 20cm length.

CFRP was used to strengthen some beams.

The variable parameters are the opening height, the percentage of cut web reinforcement, the distance between the opening edge and the nearest unaffected web reinforcement, the shear span to depth ratio and type of strengthening, as well as concrete strength.

The pattern of cracks, final mode of failure, cracking load, failure load and deformational characteristics (deflection, and strains) were recorded, analyzed and discussed.

Finally, some important conclusions were reported